Human herpesvirus 8 (HHV8), also known as Kaposi's sarcoma- associated herpesvirus (KSHV), is a herpesvirus recently discovered by representational difference analysis in Kaposi's sarcoma lesions from AIDS patients. Recent molecular and epidemiologic studies show that HHV8 is a sexually-transmitted, blood-borne DNA tumor virus associated with several cancers. There are 3 primary goals of this component of the STD Cooperative Research Center. Aim 1: To identify risk factors for HHV8 sexual transmission to women, using cross-sectional and longitudinal studies correlating virologic results with other sexually transmitted infections and high-risk behaviors. HHV8 infection will be determined using HHV8- specific serologic assays to HHV8 latent and lytic antigens. Aim 2: To characterize the biology and epidemiology of HHV8 infection in women through the identification of viral reservoirs, serial determination of viral burden, and examination of HHV8 molecular epidemiology by examining viral strain during pregnancy and the risk of maternal transmission of HHV8 to offspring by following HHV8-seropositive women during pregnancy and their offspring during infancy, to determine the potential risk of vertical HHV8 transmission, and the factors and high-risk behaviors that may influence vertical transmission. Our study cohort is from the STD Cooperative Research Center. We have shown a 5% HHV8-seroprevalence in healthy blood donors in San Antonio, with a 22% seroprevalence among women at this STD Clinic. The Cooperative Research Center provides an exceptional opportunity to characterize the behavioral and concomitant medical risk factors that account for the increased rate of HHV8 infection in women.